Synergists to aerosol insecticides



Patented Apr. 4, 1944 2,345,904 SYNERGISTS T AEROSOL INSECTICIDESWilliam N. Sullivan, Washington, D. 0., and Lyle D. Goodhue, Berwyn,Md., assignors to the United States of America as represented by ClaudeR. Wickard, Secretary of Agriculture, and his successors in oflice NoDrawing. Original application September 30,

1941, Serial No. 412,960.

Divided and this application January 7, 1944, Serial No. 517,371

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 3 Claims.

This application is made under the act of March 3, 1883, as amended bythe act of April 0 30, 1928, and the invention herein described andclaimed, if patented, may be manufactured and used by or for theGovernment of the United States of America for governmental purposeswithout the payment to us of any royalty there- This is a division ofour copending application for patent, Serial No. 412,960, filedSeptember 30, 1941. a I Our invention relates to materials which willincrease the effectiveness of insecticides in aerosol form. 1

Certain agents which may or may not be toxic in themselves when added toaerosol insecticides greatlyincrease the rate of mortality. Theincreased toxicity obtained by the combination of such materials isoften referred to as synergism and the added material a synergist.Therefore, in these terms, the general object of our invention is theprovision of materials suit able as synergists for aerosol insecticides.

Another object of our invention is the provision of agents which willnot only increase the insecticidal action of materials known 'to possesssome toxicity, but, which will also impart insecticidal properties tomaterials which are known to be non-toxic or to have a very lowtoxicity.

A further object of our invention is the provision of such agents actingas synergists, which can be applied by dispersion simultaneously withand by the same methods used for the preparation of aerosolinsecticides.

We have found that materials suitable for the purposes of this inventionbelong most frequently to the class of chemical compounds which I aresurface active in non-aqueous solvents or production can be used withdifferent types of synergists. In this class of chemical compounds wehave found the fatty acids, the ,mono esters of fatty acids and ethyleneor propylene glycol, of glycerine or sorbitol, to be especially suitableas well as fatty acids in combination with atnines such asmethanolamine, ulfonated aryl]and alkyl 1 radicals alone or combinedwith an amine,"

There are many processes which can be used to apply these materials inthef-form of aerosols; such as spraying into the atmosphere f vaporizaetion, by chemical reaction, byspraying on a heated surface, and soforth. Although this} invention is not limited to any particular methodof application, our preferred *method of/ application comprisesdissolving the synergist in the; insecticide, if the insecticide is aliquid, or dissolving it in some solvent common to'- both if a solid,and spraying the solutionon a heated surface, whereby an aerosol isformed composed of both the synergist and the insecticide.

, A synergist to an insecticide in aerosolform is not necessarily also asynergist to an insecticide in spray form, even of the same compound.Actual tests have disclosed that an agent which possesses little or noeffect as a synergist to an insecticidal spray may be extremelyeffective as a synergist to an insecticidal aerosol. The rea son forthis is not apparent, but it would seem that the mere wetting of theinsect cannot explain the action.

The following results were obtained using synergists in accordance withthis invention. These results were obtained on the basis of preliminarytests first carried out in a small chamber of '7 cu. ft. and then on alarger scale in a 216 cu. ft. chamber. In each test from 500 to 600files were used. Six-tenths of a pound of o-dichlorobenzene per 1000 cu.ft. gave only a 2% kill. However, when mixed with 0.16 lb. of oleic acidas a synergist, a kill was obtained. This same quantity of oleic acid,when used alone under the same conditions gave only a 1% kill. Lauricacid when used alone inthe same amount, namely, 0.16 lb. per 1000 cu.it, gave only a 1% kill, but. when used as a synergist with 0.6 lb. ofo-diclilorobenzene per 1000 cu. it. a kill was obtained.

The same synergists were tested at other concentrations and it was foundthat little is gained by adding more than 10%.

The following is a list of substances which were tested as synergists ata concentration of 0.06 lb. in 0.6 lb. of o-dichlorobenzene per 1000 cu.it. against the housefly, the percentage of kill in each case beingindicated in the right hand column:

Percent kill Spermaceti 37 Diglycol laurate 48 Sulfonated naphthalene 60Salicylic ac 91 Propylene glycol oleate 28 Myristic ac 49 Propyleneglycol laurate 74 Sorbitol laurate .59 Monoglycol laurate .56Triethanolamine oleate 56 Lauryl sulfate 70 Other insecticides were usedagainst the American and German cockroach at a concentration ways lessthan 100% and usually less than 50%.

In a 1100 cu. ft. room, naturally infested with cockroaches, more than5000 were killed in 18 hours and none were found living, using 1 /2 lbs.of o-dichlorobenzene with 3% lauric acid and 2% oleic acid. Excellentresults were also obtained in a 3200 cu. ft. room.

Tests were also conducted against the carpet beetle larva, the confusedflour beetles and crickets. The halogenated esters in combination withany one of the synergists mentioned above are extremely toxic to theconfused flour beetle and produce a high mortality to the carpet beetlelarva.

Among 80 compounds tested against the housefly in the form of aerosols,in combination with synergists of the type mentioned above, are 3-chloroacenaphthene, Z-chlorofluorene, 3-chlorodibenzofuran, chlorinateddiphenyls, halogenated naphthalenes, halogenated esters, halogenatedketones, carbazole, thiocresol and halogenated phenols. The synergistwas shown to be responsible in each case for an increase in toxicity.

Having thus described our invention, we claim: 1. An insecticide inaerosol form comprising 3- chlorodibenzofuran and an agent chosen fromthe group consisting of dlglycoi laurate, propylene glycol oleate,propylene glycol laurate, sorbitol laurate, and monoglycol laurate.

2. An insecticide in aerosol form comprising 3- chlorociibenzofuran andsulionated naphthalene.

3. An insecticide in aerosol form comprising 3- chlorodibenzofuran andlauryl sulfate.

' W N. SULLIVAN.

LYLE D. GOODHUE.

